Crimp Terminal Laser Welding Keyhole Prevention
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Solution Overview
Problem
Laser welding of overlapped portions in crimp terminals can result in incomplete seals due to the formation of keyholes, leading to potential corrosion and reduced quality of the crimp terminal connections, especially when using aluminum conductors.
Innovation Solution
A crimp terminal design with a tubular crimp portion and a sealing portion featuring two widthwise joining trajectories, where one trajectory overlaps the other, with the ends of the trajectories deviated on the opposite side of the crimp portion, ensuring a complete seal without keyhole formation, and a method involving laser welding with varying power levels to achieve this configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser welding is performed on the overlapped portion to seal the electric wire, then productivity and formability are improved, but keyholes may form at the end of welding causing incomplete seals and potential corrosion
Solution Approach 1:
The sealing process is divided into two distinct stages: first welding the butted portion at the connector end, then welding the overlapped portion at the opposite end. This segmentation ensures that each welding operation can be optimized independently, preventing keyhole formation while maintaining high productivity through continuous automated processing.
Solution Approach 2:
The butted portion is welded first as a preliminary action before welding the overlapped portion. This preliminary welding creates a stable structural foundation that prevents deformation and keyhole formation during the subsequent overlapped portion welding, ensuring complete sealing without compromising reliability.
2Object-affected harmful factors
If the crimp portion is molded with resin to protect the aluminum conductor, then corrosion protection is improved, but the connector size increases and manufacturing processes become cumbersome
Solution Approach 1:
The resin molding process is extracted and replaced with a metal cap sealing approach. The metal cap is crimped over the aluminum conductor and welded to the terminal, providing corrosion protection without requiring bulky resin molding. This extraction eliminates the associated complexity in manufacturing processes while maintaining effective corrosion protection.
Solution Approach 2:
The chemical bonding mechanism of resin molding is replaced with mechanical crimping and laser welding. The metal cap is mechanically crimped onto the conductor and then securely joined through laser welding, providing equivalent or superior corrosion protection with simpler, more efficient manufacturing processes and reduced connector size.
3Weight of moving object
If aluminum conductor is used for lightweighting, then weight is reduced, but dissimilar metal corrosion occurs at the connection between aluminum conductor and copper terminal
Solution Approach 1:
A metal cap made of aluminum or aluminum alloy is introduced as an intermediary component between the aluminum conductor and copper terminal. This intermediary cap is crimped over the aluminum conductor and welded to the terminal, creating a protective barrier that prevents direct contact between dissimilar metals, thereby eliminating galvanic corrosion while maintaining the lightweight advantage of aluminum conductors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively seals the overlapped portion without lowering the quality of the crimp terminal, preventing corrosion and ensuring a reliable electrical connection.
Implementation Method 1
at the sealing portion, the substrate is bent and lapped and continuously joined from one end portion to another end portion of the overlapped portion
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
To weld the overlapped portion accurately without lowering the quality of the crimp terminal. A crimp terminal (10) is provided with a crimp portion (12) formed in a tubular shape with an electrically conductive the substrate and configured to crimp join with an electric wire, and a sealing portion (14, 15, 16, 17) formed at one end of the crimp portion and seals against an electric wire to be crimp joined to the crimp portion, and at the sealing portion, the substrate is bent and lapped and continuously joined from one end portion to another end portion of the overlapped portion, and one end of a joining trajectory is at a position that is deviated on a side opposite of the crimp portion with respect to the sealing portion.